SYSAV incineration plant
in
Malmö, Sweden
capable of handling 25
metric tons
(28 short
tons) per
hour household waste. To
the left of the main
stack, a new identical
oven line is under
construction (March
2007).

Incineration is a
waste
treatment process that
involves the
combustion
of
organic
substances contained in waste
materials.[1]
Incineration and other high
temperature waste treatment systems
are described as "thermal
treatment". Incineration
of waste materials converts the
waste into
ash,
flue gas,
and heat. The ash is mostly formed
by the
inorganic
constituents of the waste, and may
take the form of solid lumps or
particulates
carried by the flue gas. The flue
gases must be cleaned of gaseous and
particulate pollutants before they
are dispersed into the
atmosphere.
In some cases, the heat generated by
incineration can be used to generate
electric power.

In
several countries, there are still
concerns from experts and local
communities about the environmental
impact of incinerators (see
arguments
against incineration).

In
some countries, incinerators built
just a few decades ago often did not
include a
materials
separation to remove
hazardous,
bulky
or
recyclable
materials before combustion. These
facilities tended to risk the health
of the plant workers and the local
environment due to inadequate levels
of gas cleaning and combustion
process control. Most of these
facilities did not generate
electricity.

Incinerators reduce the solid mass
of the original waste by 80¨C85% and
the volume (already compressed
somewhat in
garbage trucks)
by 95-96 %, depending on composition
and degree of recovery of materials
such as metals from the ash for
recycling.[2]
This means that while incineration
does not completely replace
landfilling,
it significantly reduces the
necessary volume for disposal.
Garbage trucks
often reduce the volume of waste in
a built-in compressor before
delivery to the incinerator.
Alternatively, at landfills, the
volume of the uncompressed garbage
can be reduced by approximately 70%[citation
needed] by
using a stationary steel compressor,
albeit with a significant energy
cost. In many countries, simpler
waste
compaction is a common
practice for compaction at
landfills.

Incineration has particularly strong
benefits for the treatment of
certain
waste types
in
niche
areas such as
clinical
wastes and certain
hazardous
wastes where
pathogens
and
toxins
can be destroyed by high
temperatures. Examples include
chemical multi-product plants with
diverse toxic or very toxic
wastewater streams, which cannot be
routed to a conventional wastewater
treatment plant.

Waste combustion is particularly
popular in countries such as Japan
where land is a scarce resource.
Denmark and Sweden have been leaders
in using the energy generated from
incineration for more than a
century, in localised
combined heat
and power facilities
supporting
district
heating schemes.[3]
In 2005, waste incineration produced
4.8 % of the electricity consumption
and 13.7 % of the total domestic
heat consumption in Denmark.[4]
A number of other European countries
rely heavily on incineration for
handling municipal waste, in
particular
Luxembourg,
the Netherlands, Germany and France.[2]

An
incinerator is a
furnace
for burning
waste.
Modern incinerators include
pollution mitigation equipment such
as
flue
gas cleaning. There are various
types of incinerator plant design:
moving grate, fixed grate,
rotary-kiln, and fluidised bed.

The burn pile, or
burn pit
is one of the simplest and earliest
forms of waste disposal, essentially
consisting of a mound of combustible
materials piled on bare ground and
set on fire. Indiscriminate piles of
household waste are strongly
discouraged and may be illegal in
urban areas, but are permitted in
certain rural situations such as
clearing forested land for farming,
where the stumps are uprooted and
burned.[6]
Rural burn piles of organic yard
waste are also sometimes permitted,
though not
asphalt
shingles, plastics, or
other
petroleum
products.[6]

Burn piles can and have spread
uncontrolled fires, for example if
wind blows burning material off the
pile into surrounding combustible
grasses or onto buildings. As
interior structures of the pile are
consumed, the pile can shift and
collapse, spreading the burn area.
Even in a situation of no wind,
small lightweight ignited embers can
lift off the pile via
convection,
and waft through the air into
grasses or onto buildings, igniting
them.

The burn barrel is a somewhat more
controlled form of private waste
incineration, containing the burning
material inside a metal barrel, with
a metal grating over the exhaust.
The barrel prevents the spread of
burning material in windy
conditions, and as the combustibles
are reduced they can only settle
down into the barrel. The exhaust
grating helps to prevent the spread
of burning embers. Typically steel
55-gallon drums are used as burn
barrels, with air vent holes cut or
drilled around the base for air
intake.[7]
Over time the very high heat of
incineration causes the metal to
oxidize and rust, and eventually the
barrel itself is consumed by the
heat and must be replaced.

Private burning of dry
cellulosic/paper products is
generally clean-burning, producing
no visible smoke, but the large
amount of plastics in household
waste can cause private burning to
create a public nuisance and health
hazard, generating acrid odors and
fumes that make eyes burn and water.
The temperatures in a burn barrel
are not regulated, and usually do
not reach high enough or for enough
time to completely break down
chemicals such as
dioxin
in plastics and other waste
chemicals. Therefore plastics and
other petroleum products must be
separated and sent to commercial
waste disposal facilities.

In
The United States, private rural
incineration is typically permitted
so long as it is not a nuisance to
others, does not pose a risk of fire
such as in dry conditions, and the
fire is clean-burning, producing no
visible smoke. However, many states,
such as New York, Minnesota, and
Wisconsin, have laws against private
burn barrels due to EPA findings
that one household burning their own
waste can release more dioxins and
furans annually than a modern
incinerator processing 1,000 tons
per day.[8]
People intending to burn waste may
be required to contact a state
agency in advance to check current
fire risk and conditions, and to
alert officials of the controlled
fire that will occur.[9]

Control room of a
typical moving grate
incinerator overseeing
two boiler lines

The typical incineration plant for
municipal
solid waste is a moving
grate incinerator. The moving grate
enables the movement of waste
through the combustion chamber to be
optimised to allow a more efficient
and complete combustion. A single
moving grate boiler can handle up to
35 metric tons (39 short tons) of
waste per hour, and can operate
8,000 hours per year with only one
scheduled stop for inspection and
maintenance of about one month's
duration.[10]
Moving grate incinerators are
sometimes referred to as Municipal
Solid Waste Incinerators (MSWIs).

The waste is introduced by a
waste crane
through the "throat" at one end of
the grate, from where it moves down
over the descending grate to the ash
pit in the other end. Here the ash
is removed through a water lock.

Municipal solid waste in
the furnace of a moving
grate incinerator
capable of handling 15
metric tons (17 short
tons) of waste per hour.
The holes in the grate
elements supplying the
primary combustion air
are visible.

Part of the combustion air (primary
combustion air) is supplied through
the grate from below. This air flow
also has the purpose of cooling the
grate itself. Cooling is important
for the mechanical strength of the
grate, and many moving grates are
also water cooled internally.

Secondary combustion air is supplied
into the boiler at high speed
through nozzles over the grate. It
facilitates complete combustion of
the flue gases by introducing
turbulence
for better mixing and by ensuring a
surplus of oxygen. In
multiple/stepped hearth
incinerators, the secondary
combustion air is introduced in a
separate chamber downstream the
primary combustion chamber.

According to the European
Waste
Incineration Directive,
incineration plants must be designed
to ensure that the
flue gases
reach a temperature of at least
850 ¡ãC
(1,560 ¡ãF) for 2 seconds in
order to ensure proper breakdown of
toxic organic substances. In order
to comply with this at all times, it
is required to install backup
auxiliary burners (often fueled by
oil), which are fired into the
boiler in case the
heating value
of the waste becomes too low to
reach this temperature alone.

The
flue gases
are then cooled in the
superheaters,
where the heat is transferred to
steam, heating the steam to
typically
400 ¡ãC
(752 ¡ãF) at a pressure of 40
bars
(580 psi)
for the electricity generation in
the
turbine.
At this point, the flue gas has a
temperature of around
200 ¡ãC
(392 ¡ãF), and is passed to
the
flue gas
cleaning system.

In
Scandinavia
scheduled maintenance is always
performed during summer, where the
demand for
district
heating is low. Often
incineration plants consist of
several separate 'boiler lines'
(boilers and flue gas treatment
plants), so that waste can continue
to be received at one boiler line
while the others are subject to
revision.

The older and simpler kind of
incinerator was a brick-lined cell
with a fixed metal grate over a
lower ash pit, with one opening in
the top or side for loading and
another opening in the side for
removing incombustible solids called
clinkers.
Many small incinerators formerly
found in apartment houses have now
been replaced by
waste
compactors.

The
rotary-kiln
incinerator[11]
is used by municipalities and by
large industrial plants. This design
of incinerator has 2 chambers: a
primary chamber and secondary
chamber. The primary chamber in a
rotary kiln incinerator consist of
an inclined refractory lined
cylindrical tube. Movement of the
cylinder on its axis facilitates
movement of waste. In the primary
chamber, there is conversion of
solid fraction to gases, through
volatilization, destructive
distillation and partial combustion
reactions. The secondary chamber is
necessary to complete gas phase
combustion reactions.

The clinkers spill out at the end of
the cylinder. A tall flue gas stack,
fan, or steam jet supplies the
needed
draft.
Ash drops through the grate, but
many particles are carried along
with the hot gases. The particles
and any combustible gases may be
combusted in an "afterburner".[12]

A
strong airflow is forced through a
sandbed. The air seeps through the
sand until a point is reached where
the sand particles separate to let
the air through and mixing and
churning occurs, thus a
fluidised bed
is created and fuel and waste can
now be introduced.

The sand with the pre-treated waste
and/or fuel is kept suspended on
pumped air currents and takes on a
fluid-like character. The bed is
thereby violently mixed and agitated
keeping small inert particles and
air in a fluid-like state. This
allows all of the mass of waste,
fuel and sand to be fully circulated
through the furnace.

Furniture factory sawdust
incinerators need much attention as
these have to handle resin powder
and many flammable substances.
Controlled combustion, burn back
prevention systems are essential as
dust when suspended resembles the
fire catch phenomenon of any liquid
petroleum gas.

The heat produced by an incinerator
can be used to generate steam which
may then be used to drive a
turbine
in order to produce
electricity.
The typical amount of net energy
that can be produced per tonne
municipal waste is about 2/3 MWh of
electricity and 2 MWh of district
heating.[2]
Thus, incinerating about 600 metric
tons (660 short tons) per day of
waste will produce about 400 MWh of
electrical energy per day (17 MW
of electrical power continuously for
24 hours) and 1200 MWh of district
heating energy each day.

In
a study from 1994, Delaware Solid
Waste Authority found that, for same
amount of produced energy,
incineration plants emitted fewer
particles, hydrocarbons and less SO2,
HCl, CO and NOx than
coal-fired
power plants, but more than
natural gas
fired power plants.[13]
According to
Germany's
Ministry of the Environment,
waste incinerators reduce the amount
of some atmospheric pollutants by
substituting power produced by
coal-fired plants with power from
waste-fired plants.[14]

The most publicized concerns from
environmentalists about the
incineration of municipal solid
wastes (MSW) involve the fear that
it produces significant amounts of
dioxin
and
furan
emissions.[15]
Dioxins and furans are considered by
many to be serious health hazards.

In
2005, The Ministry of the
Environment of Germany, where there
were 66 incinerators at that time,
estimated that "...whereas in 1990
one third of all dioxin emissions in
Germany came from incineration
plants, for the year 2000 the figure
was less than 1 %.
Chimneys
and tiled stoves in private
households alone discharge
approximately 20 times more dioxin
into the environment than
incineration plants."[14]

According to the
United States
Environmental Protection Agency,
incineration plants are no longer
significant sources of dioxins and
furans. In 1987, before the
governmental regulations required
the use of emission controls, there
was a total of 10,000 grams (350 oz)
of dioxin emissions from US
incinerators. Today, the total
emissions from the 87 plants are 10
grams (0.35 oz) annually, a
reduction of 99.9 %.

Backyard barrel burning of household
and
garden wastes,
still allowed in some rural areas,
generates 580 grams (20 oz) of
dioxins annually. Studies conducted
by the US-EPA[16]
demonstrate that the emissions from
just one family using a burn barrel
produced more emissions than an
incineration plant disposing of 200
metric tons (220 short tons) of
waste per day by 1997 and five times
that by 2007 due to increased
chemicals in household trash and
decreased emissions by municipal
incinerators using better technology[citation
needed].

Generally, the breakdown of dioxin
requires exposure of the molecular
ring to a sufficiently high
temperature so as to trigger thermal
breakdown of the strong molecular
bonds holding it together. Small
pieces of fly ash may be somewhat
thick, and too brief an exposure to
high temperature may only degrade
dioxin on the surface of the ash.
For a large volume air chamber, too
brief an exposure may also result in
only some of the exhaust gases
reaching the full breakdown
temperature. For this reason there
is also a time element to the
temperature exposure to ensure
heating completely through the
thickness of the fly ash and the
volume of waste gases.

There are trade-offs between
increasing either the temperature or
exposure time. Generally where the
molecular breakdown temperature is
higher, the exposure time for
heating can be shorter, but
excessively high temperatures can
also cause wear and damage to other
parts of the incineration equipment.
Likewise the breakdown temperature
can be lowered to some degree but
then the exhaust gases would require
a greater lingering period of
perhaps several minutes, which would
require large/long treatment
chambers that take up a great deal
of treatment plant space.

A
side effect of breaking the strong
molecular bonds of dioxin is the
potential for breaking the bonds of
nitrogen gas (N2)
and oxygen gas (O2)
in the supply air. As the exhaust
flow cools, these highly reactive
detached atoms spontaneously reform
bonds into reactive oxides such as
NOx
in the flue gas, which can result in
smog
formation and
acid rain
if they were released directly into
the local environment. These
reactive oxides must be further
neutralized with
selective
catalytic reduction (SCR)
or
selective
non-catalytic reduction
(see below).

The temperatures needed to break
down dioxin are typically not
reached when burning of plastics
outdoors in a burn barrel or garbage
pit, causing high dioxin emissions
as mentioned above. While plastic
does usually burn in an open-air
fire, the dioxins remain after
combustion and either float off into
the atmosphere, or may remain in the
ash where it can be leached down
into groundwater when rain falls on
the ash pile.

Modern municipal incinerator designs
include a high temperature zone,
where the flue gas is ensured to
sustain a temperature above
850 ¡ãC
(1,560 ¡ãF) for at least
2 seconds before it is cooled down.
They are equipped with auxiliary
heaters to ensure this at all times.
These are often fueled by oil, and
normally only active for a very
small fraction of the time.

For very small municipal
incinerators, the required
temperature for thermal breakdown of
dioxin may be reached using a
high-temperature electrical heating
element, plus a
selective
catalytic reduction
stage.

As
for other complete combustion
processes, nearly all of the carbon
content in the waste is emitted as
CO2 to the atmosphere.
MSW
contains approximately the same mass
fraction of carbon as CO2
itself (27%), so incineration of 1
ton of MSW produces approximately 1
ton of CO2.

If
the waste was
landfilled,
1 ton of MSW would produce
approximately 62
cubic metres
(2,200 cu ft)
methane
via the
anaerobic
decomposition of the
biodegradable
part of the waste. Since the
global warming
potential of methane is
21 and the weight of 62 cubic meters
of methane at 25 degrees Celsius is
40.7 kg, this is equivalent to 0.854
ton of CO2, which is less
than the 1 ton of CO2
which would have been produced by
incineration. In some countries,
large amounts of
landfill gas
are collected, but still the global
warming potential of the landfill
gas emitted to atmosphere in the US
in 1999 was approximately 32 %
higher than the amount of CO2
that would have been emitted by
incineration.[17]

In
addition, nearly all biodegradable
waste has biological origin. This
material has been formed by plants
using atmospheric CO2
typically within the last growing
season. If these plants are regrown
the CO2 emitted from
their combustion will be taken out
from the atmosphere once more.

Such considerations are the main
reason why several countries
administrate incineration of the
biodegradable part of waste as
renewable
energy.[18]
The rest ¨C mainly plastics and other
oil and gas derived products ¨C is
generally treated as
non-renewables.

Different results for the CO2
footprint of incineration can be
reached with different assumptions.
Local conditions (such as limited
local district heating demand, no
fossil fuel generated electricity to
replace or high levels of aluminum
in the waste stream) can decrease
the CO2 benefits of
incineration. The methodology and
other assumptions may also influence
the results significantly. For
example the methane emissions from
landfills occurring at a later date
may be neglected or given less
weight, or biodegradable waste may
not be considered CO2
neutral. A study by Eunomia Research
and Consulting in 2008 on potential
waste treatment technologies in
London demonstrated that by applying
several of these (according to the
authors) unusual assumptions the
average existing incineration plants
performed poorly for CO2
balance compared to the theoretical
potential of other emerging waste
treatment technologies.[19]

[]
Other emissions

The
steam
content in the flue may produce
visible fume from the stack, which
can be perceived as a
visual
pollution. It may be
avoided by decreasing the steam
content by
flue gas
condensation and
reheating, or by increasing the flue
gas exit temperature well above its
dew point. Flue gas condensation
allows the latent heat of
vaporization of the water to be
recovered, subsequently increasing
the thermal efficiency of the plant.

[]
Flue gas cleaning

The quantity of pollutants in the
flue gas from incineration plants is
reduced by several processes.

Particulate is collected by
particle
filtration, most often
electrostatic
precipitators (ESP)
and/or
baghouse
filters. The latter are
generally very efficient for
collecting
fine particles.
In an investigation by the
Ministry of
the Environment of Denmark
in 2006, the average particulate
emissions per energy content of
incinerated waste from 16 Danish
incinerators were below 2.02 g/GJ
(grams per energy content of the
incinerated waste). Detailed
measurements of fine particles with
sizes below 2.5 micrometres
(PM2.5)
were performed on three of the
incinerators: One incinerator
equipped with an ESP for particle
filtration emitted 5.3 g/GJ fine
particles, while two incinerators
equipped with baghouse filters
emitted 0.002 and 0.013 g/GJ PM2.5.
For ultra fine particles (PM1.0),
the numbers were 4.889 g/GJ PM1.0
from the ESP plant, while emissions
of 0.000 and 0.008 g/GJ PM1.0
were measured from the plants
equipped with baghouse filters.[20][21]

NOx
is either reduced by catalytic
reduction with ammonia in a
catalytic
converter (selective
catalytic reduction, SCR)
or by a high temperature reaction
with ammonia in the furnace (selective
non-catalytic reduction,
SNCR). Urea may be substituted for
ammonia as the reducing reagent but
must be supplied earlier in the
process so that it can hydrolyze
into ammonia. Substitution of urea
can reduce costs and potential
hazards associated with storage of
anhydrous ammonia.

Heavy metals are often
adsorbed
on injected
active carbon
powder, which is collected by the
particle filtration.

[]
Solid outputs

Incineration produces
fly ash
and
bottom ash
just as is the case when coal is
combusted. The total amount of ash
produced by municipal solid waste
incineration ranges from 4 to 10 %
by volume and 15-20 % by weight of
the original quantity of waste,[2][23]
and the fly ash amounts to about
10-20 % of the total ash.[citation
needed] The fly
ash, by far, constitutes more of a
potential health hazard than does
the bottom ash because the fly ash
often contain high concentrations of
heavy metals such as
lead,
cadmium,
copper
and
zinc
as well as small amounts of dioxins
and furans.[24]
The bottom ash seldom contain
significant levels of heavy metals.
In testing over the past decade, no
ash from an incineration plant in
the USA has ever been determined to
be a
hazardous
waste.[citation
needed] At
present although some historic
samples tested by the incinerator
operators' group would meet the
being ecotoxic criteria at present
the EA say "we have agreed" to
regard incinerator bottom ash as
"non-hazardous" until the testing
programme is complete.[citation
needed]

Odor
pollution can be a problem with
old-style incinerators, but odors
and dust are extremely well
controlled in newer incineration
plants. They receive and store the
waste in an enclosed area with a
negative pressure with the airflow
being routed through the boiler
which prevents
unpleasant
odors from escaping into
the atmosphere. However, not all
plants are implemented this way,
resulting in inconveniences in the
locality.

An
issue that affects community
relationships is the increased road
traffic of
waste
collection vehicles to
transport municipal waste to the
incinerator. Due to this reason,
most incinerators are located in
industrial areas. This problem can
be avoided to an extent through the
transport of waste by rail from
transfer stations.

[]
Debate

Use of incinerators for
waste
management is
controversial. The debate over
incinerators typically involves
business interests (representing
both waste generators and
incinerator firms), government
regulators, environmental activists
and local citizens who must weigh
the economic appeal of local
industrial activity with their
concerns over health and
environmental risk.

People and organizations
professionally involved in this
issue include the
U.S.
Environmental Protection Agency
and a great many local and national
air quality regulatory agencies
worldwide.

[]
Arguments for incineration

The concerns over the health
effects of
dioxin
and
furan
emissions have been
significantly lessened by
advances in emission control
designs and very stringent new
governmental regulations that
have resulted in large
reductions in the amount of
dioxins and furans emissions.[14]

The U.K.
Health
Protection Agency
concluded in 2009 that "Modern,
well managed incinerators make
only a small contribution to
local concentrations of air
pollutants. It is possible that
such small additions could have
an impact on health but such
effects, if they exist, are
likely to be very small and not
detectable.".[25]

Incineration plants can generate
electricity and heat that can
substitute power plants powered
by other fuels at the regional
electric and
district
heating grid, and
steam supply for industrial
customers. Incinerators and
other waste-to-energy plants
generate at least partially
biomass-based renewable energy
that offsets greenhouse gas
pollution from coal-, oil- and
gas-fired power plants.[26]
The E.U. considers energy
generated from biogenic waste
(waste with biological origin)
by incinerators as non-fossil
renewable energy under its
emissions caps. These greenhouse
gas reductions are in addition
to those generated by the
avoidance of landfill methane.

The bottom ash residue remaining
after combustion has been shown
to be a non-hazardous solid
waste that can be safely put
into landfills or recycled as
construction aggregate. Samples
are tested for ecotoxic metals.[27]

The Maishima waste
treatment center in
Osaka, designed by
Friedensreich
Hundertwasser, uses
heat for power
generation.

Fine
particles can be
efficiently removed from the
flue gases with
baghouse
filters. Even though
approximately 40 % of the
incinerated waste in Denmark was
incinerated at plants with no
baghouse filters, estimates
based on measurements by the
Danish Environmental Research
Institute showed that
incinerators were only
responsible for approximately
0.3 % of the total domestic
emissions of
particulate smaller
than 2.5 micrometres
(PM2.5)
to the atmosphere in 2006.[20][21]

Incineration of municipal solid
waste avoids the release of
methane.
Every ton of MSW incinerated,
prevents about one ton of carbon
dioxide equivalents from being
released to the atmosphere.[17]

Most municipalities that operate
incineration facilities have
higher recycling rates than
neighboring cities and counties
that do not send their waste to
incinerators.[28]
This is in part due to enhanced
recovery of ceramic materials
reused in construction, as well
as ferrous and in some cases
non-ferrous metals that can be
recovered from combustion
residue.[29]
Metals recovered from ash would
typically be difficult or
impossible to recycle through
conventional means, as the
removal of attached combustible
material through incineration
provides an alternative to
labor- or energy-intensive
mechanical separation methods.

Volume of combusted waste is
reduced by approximately 90%,
increasing the life of
landfills. Ash from modern
incinerators is vitrified at
temperatures of
1,000 ¡ãC
(1,830 ¡ãF) to
1,100 ¡ãC
(2,010 ¡ãF), reducing the
leachability and toxicity of
residue. As a result, special
landfills are generally no
longer required for incinerator
ash from municipal waste
streams, and existing landfills
can see their life dramatically
increased by combusting waste,
reducing the need for
municipalities to site and
construct new landfills.[30][31]

[rguments
against incineration

The Scottish Protection Agency's
(SEPA) comprehensive health
effects research concluded
"inconclusively" on health
effects in Oct. 2009. The
authors stress, that even though
no conclusive evidence of
non-occupational health effects
from incinerators were found in
the existing literature, "small
but important effects might be
virtually impossible to detect".
The report highlights
epidemiological deficiencies in
previous UK health studies and
suggests areas for future
studies.[32]
The U.K.
Health
Protection Agency
produced a lesser summary in
September 2009.[25]
Many toxiocologists criticise
and dispute this report as not
being comprehensive
epidemiologically, thin on peer
review and the effects of fine
particle effects on health.[citation
needed]

The highly toxic
fly ash
must be safely disposed of. This
usually involves additional
waste miles and the need for
specialist toxic waste landfill
elsewhere. If not done properly,
it may cause concerns for local
residents.[33][34]

Some people are still concerned
about the health effects of
dioxin
and
furan
emissions into the atmosphere
from old incinerators;
especially during start up and
shut down, or where filter
bypass is required.

Incinerator Bottom Ash (IBA) has
elevated levels of heavy metals
with ecotoxicity concerns if not
reused properly. Some people
have the opinion that IBA reuse
is still in its infancy and is
still not considered to be a
mature or desirable product,
despite additional engineering
treatments. Concerns of IBA use
in foam concrete have been
expressed by the UK Health and
Safety Executive in 2010
following several construction
and demolition explosions. In
its guidance document, IBA is
currently banned from use by the
UK Highway Authority in concrete
work until these incidents have
been investigated.[35]

Alternative technologies are
available or in development such
as
Mechanical
Biological Treatment,
Anaerobic
Digestion (MBT/AD),
Autoclaving or
Mechanical
Heat Treatment (MHT)
using steam or
plasma arc
gasification (PGP),
which is incineration using
electrically produced extreme
high temperatures, or
combinations of these
treatments. Erection of
incinerators compete with the
development and introduction of
other emerging technologies. A
UK government WRAP report,
August 2008 found that in the UK
median incinerator costs per ton
were generally higher than those
for MBT treatments by £18 per
metric ton;
and £27 per metric ton for most
modern (post 2000) incinerators.[36][37]

Building and operating waste
processing plants such as
incinerators requires long
contract periods to recover
initial investment costs,
causing a long term lock-in.
Incinerator lifetimes normally
range 25¨C30 years. This was
highlighted by Peter Jones,
OBE,
the Mayor of London's waste
representative in April 2009.[38]

Incinerators produce
fine
particles in the
furnace. Even with modern
particle filtering of the flue
gases, a small part of these is
emitted to the atmosphere. PM2.5
is not separately regulated in
the European
Waste
Incineration Directive,
even though they are repeatedly
correlated spatially to infant
mortality in the UK (M.Ryan's
ONS data based maps around the
EfW/CHP waste incinerators at
Edmonton, Coventry, Chineham,
Kirklees and Sheffield).[39][40][41]
Under WID there is no
requirement to monitor stack top
or downwind incinerator PM2.5
levels.[42]
Several European doctors
associations (including cross
discipline experts such as
physicians, environmental
chemists and toxicologists) in
June 2008 representing over
33,000 doctors wrote a keynote
statement directly to the
European Parliament citing
widespread concerns on
incinerator particle emissions
and the absence of specific fine
and ultrafine particle size
monitoring or in depth industry/
government epidemiological
studies of these minute and
invisible incinerator particle
size emissions.[43]

Local communities are often
opposed to the idea of locating
waste processing plants such as
incinerators in their vicinity
(the
Not In My
Back Yard
phenomenon). Studies in
Andover,
Massachusetts
strongly correlated 10% property
devaluations with close
incinerator proximity.[44]

A
2008 Eunomia report found that
under some circumstances and
assumptions, incineration causes
less CO2 reduction
than other emerging
EfW
and
CHP
technology combinations for
treating residual mixed waste.[19]
The authors found that CHP
incinerator technology without
waste recycling ranked 19 out of
24 combinations (where all
alternatives to incineration
were combined with advanced
waste recycling plants); being
228% less efficient than the
ranked 1 Advanced MBT maturation
technology; or 211% less
efficient than plasma
gasification/autoclaving
combination ranked 2.

Some incinerators are visually
undesirable. In many countries
they require a visually
intrusive chimney stack.

If reusable waste fractions are
handled in waste processing
plants such as incinerators in
developing nations, it would cut
out viable work for local
economies. It is estimated that
there are 1 million people
making a livelihood off
collecting waste.[48]

[ends
in incinerator use

The history of
municipal
solid waste (MSW)
incineration is linked intimately to
the history of
landfills
and other
waste
treatment technology. The
merits of incineration are
inevitably judged in relation to the
alternatives available. Since the
1970s, recycling and other
prevention measures have changed the
context for such judgements. Since
the 1990s alternative waste
treatment technologies have been
maturing and becoming viable.

Incineration is a key process in the
treatment of hazardous wastes and
clinical wastes. It is often
imperative that medical waste be
subjected to the high temperatures
of incineration to destroy
pathogens
and
toxic
contamination it contains.

[ineration
in North America

The first incinerator in the U.S.
was built in 1885 on Governors
Island in New York.[49]
In 1949, Robert C. Ross founded one
of the first hazardous waste
management companies in the U.S. He
began Robert Ross Industrial
Disposal because he saw an
opportunity to meet the hazardous
waste management needs of companies
in northern Ohio. In 1958, the
company built one of the first
hazardous waste incinerators in the
U.S.[50]
The first full-scale, municipally
operated incineration facility in
the U.S. was the Arnold O. Chantland
Resource Recovery Plant, built in
1975 and located in
Ames, Iowa.
This plant is still in operation and
produces
refuse-derived
fuel that is sent to
local power plants for fuel.[51]
The first commercially successful
incineration plant in the U.S. was
built in
Saugus,
Massachusetts in October
1975 by Wheelabrator Technologies,
and is still in operation today.[23]

There are several environmental or
waste management corporations that
transport ultimately to an
incinerator or cement kiln treatment
center. Currently (2009), there are
three main businesses that
incinerate waste: Clean Harbours,
WTI-Heritage, and Ross Incineration
Services. Clean Harbours has
acquired many of the smaller,
independently run facilities,
accumulating 5¨C7 incinerators in the
process across the U.S. WTI-Heritage
has one incinerator, located in the
southeastern corner of
Ohio
(across the Ohio River from West
Virginia).

Several old generation incinerators
have been closed; of the 186 MSW
incinerators in 1990, only 89
remained by 2007, and of the 6200
medical waste incinerators in 1988,
only 115 remained in 2003.[52]
No new incinerators were built
between 1996 and 2007. The main
reasons for lack of activity have
been:

Economics. With the increase in
the number of large inexpensive
regional landfills and, up until
recently, the relatively low
price of electricity,
incinerators were not able to
compete for the 'fuel', i.e.,
waste in the U.S.

Tax policies. Tax credits for
plants producing electricity
from waste were rescinded in the
U.S. between 1990 and 2004.

There has been renewed interest in
incineration and other
waste-to-energy technologies in the
U.S. and Canada. In the U.S.,
incineration was granted
qualification for
renewable
energy production tax credits
in 2004.[53]
Projects to add capacity to existing
plants are underway, and
municipalities are once again
evaluating the option of building
incineration plants rather than
continue landfilling municipal
wastes. However, many of these
projects have faced continued
political opposition in spite of
renewed arguments for the greenhouse
gas benefits of incineration and
improved air pollution control and
ash recycling.

Incineration in Europe

In
Europe, with the ban on landfilling
untreated waste, scores of
incinerators have been built in the
last decade, with more under
construction. Recently, a number of
municipal governments have begun the
process of contracting for the
construction and operation of
incinerators. In Europe, some of the
electricity generated from waste is
deemed to be from a 'Renewable
Energy Source (RES)' and is thus
eligible for tax credits if
privately operated. Also, some
incinerators in Europe are equipped
with waste recovery, allowing the
reuse of ferrous and non-ferrous
materials found in landfills. A
prominent example is the AEB Waste
Fired Power Plant.[54][55]

Incineration
in the United Kingdom

The technology employed in the UK
waste management industry has been
greatly lagging behind that of
Europe due to the wide availability
of landfills. The
Landfill
Directive set down by the
European Union
led to the Government of the United
Kingdom imposing
waste
legislation including the
landfill tax
and
Landfill
Allowance Trading Scheme.
This legislation is designed to
reduce the release of greenhouse
gases produced by landfills through
the use of alternative methods of
waste treatment. It is the UK
Government's position that
incineration will play an
increasingly large role in the
treatment of municipal waste and
supply of energy in the UK.

In
the UK in 2008, plans for potential
incinerator locations exists for
approximately 100 sites. These have
been interactively mapped by UK
NGO's.[56][57][58][59]

Small
incinerator units

¡¡

An example of a low
capacity, mobile
incinerator

Small scale incinerators exist for
special purposes. For example, the
small scale[60]
incinerators are aimed for
hygienically
safe destruction of medical waste in
developing
countries. Small
incinerators can be quickly deployed
to remote areas where an outbreak
has occurred to dispose of infected
animals quickly and without the risk
of cross contamination.[citation
needed]